Reproduction apparatus

ABSTRACT

A xerographic reproduction machine having control means to provide a programmed shutdown of the machine in the event of a malfunction therein.

United States Patent [191 Reehil a a1.

[ Dec. 3, 1974 REPRODUCTION APPARATUS Inventors: Edward G. Reehil, Henrietta;

Edward L. Steiner, Macedon, both of NY.

Assignee: Xerox Corporation, Stamford,

Conn.

Filed: Dec. 11, 1972 Appl. No.: 314,218

11.3. C1 355/17, 355/3 DD, 355/14, 96/14 Int. Cl. G03g 15/16, 603g 15/00 Field of Search 96/1.4; 118/2, 3; 355/3 R, 355/3 DD, l7, 14

References Cited UNITED STATES PATENTS 3,620,616 11/1971 Davidson et a1. 355/3 3,661,452 5/1972 Hewes et a1. 355/3 3,674,363 7/1972 Baller et a1. 355/14 3,717,122 2/1973 Hudson 118/636 3,751,156 8/1973 Szostak et a1 355/3 Primary ExaminerRobert P. Greiner [5 7] ABSTRACT A xerographic reproduction machine having control means to provide a programmed shutdown of the machine in the event of a malfunction therein.

6 Claims, 2 Drawing Figures REPRODUCTION APPARATUS BACKGROUND OF THE INVENTION I In an electrostatic copying machine of the type using a photoconductive layer for developing a latent electrostatic image of the document to be copied and thereafter developing and transferring the image to a copy sheet, various processing stations are utilized for uniformly charging, exposingand developing the photosensitive surface, transferring the developed image to a copy sheet, fusing the transferred image on the copy sheet, cleaning the photoreceptive surface, etc. Provision must also be made for the efficient and accurate movement of sheets of copy paper from the supply station to the transfer station of the machine.

With the increasing amount of paper work that must be accomplished in various industries in recent years, commercial automatic copier/reproduction machines have bden developed to provide extremely high speed copying of original documents. As machine speeds increase, the damage or jams thatcould occur in a machine in the .event of a malfunctionalso increases. To minimize the possibility of damage, a number of sensors are employed in the machie to monitor the various machine functions and the paper. position throughout its path in the machine. In the event of'a malfunction, the sensors, acting through the machine control system, will cause the machineto shut down.

In a high'speed xerographic copier of the type employing a photoreceptor belt, a number of images may be disposed on the belt before the sheet of paper adapted to receive the foremost image is fed from the paper supply station. In the event of a malfunction of the paper feeder, these electrostatic images would proceed through the developer and the transfer rollers to the cleaning station of the-machine wherein the-belt is ordinarily cleaned prior to the charging thereof and exposure of a new image. If the paper is not present at the transfer station when the developed image arrives thereat, the xerographic surface with the toner-image thereon can cause numerous problems. Toner may be transferred from the belt to the transfer rollers. The toner that is not transferred to the transfer roll will be conveyed by movement of the belt to the cleaning station of the machine. Since the cleaning station is designed to remove the residual toner remaining after the majority of the toner is transferred to the copy sheet, in the event that a copy sheet is not present at the transfer rolls, excess quantities of toner willreach the cleaning station, putting an undue load thereon. Besides the problems presented at the transfer station and the cleaning station, this type of operation is extremely wasteful of xerographic toner.

SUMMARY OF THE'INVENTION This invention relates to a method for minimizing problems in a zerographic machine caused by the misfeed of copy paper therethrough by discharging the electrostatic image on the photoconductive surface before that portion of the surface reaches the developer station, tie-energizing the developer, and removing the electrical bias on the transfer rolls to prevent transfer of toner thereto and minimize the possibilityof carrying excess toner to the cleaning station of the. machine.

BRIEF DISCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view of a reproduction machine showing the various processing stations therein; and, L

FIG. 2 is a schematicblock diagram of the control system to provide a programmed shutdown of the machine in the event of a paper misfeed.

DESCRIPTION OF THE PREFERRED EMBODIMENT For a general understanding of an electrostatic processing system in which the invent-ion may be incorporated, reference is bad to FIG. 1 in which various components of a system are schematically illustrated. As in most-electrostatic systems such as a xerographic machine, a light image of the original to be reproduced is projected onto the sensitized surface of a zerographic plate to form an electrostatic latent image thereon. Thereafter, the latent image is developed with an oppor sitely charged developing material comprising carrier beads and smaller powder particles triboelectrically adhering thereto to "form a xerographic powder image corresponding to the latent image on the plate surface.

The powder image is then electrostatically transferred to a support surface to which it may be fixed by a fusing device whereby the powder image is caused permanently to adhere to the support surface.

The electrostatically attractable developing material commonly used in electrostatic reproduction systems comprises a pigmented resinous powder hereinafter referred to as toner", and carrier" of larger granular beads formed from a material removed in the triboelectric series from the toner so that a triboelectric charge is generated between the toner powder and the granular carrier. The carrier also provides mechanical control .sothat the toner can be readily handled and brought into contact with the exposed xerographic surface where the toner is attracted to the electrostatic latent image from the carrier to produce a visible powder image on the xerographic surface.

In the illustrated machine, an original D to be copied is placed upona transparent support platen P, fixedly arranged in anillumination assembly generally indicated'by the reference numeral 10. While upon the platen, an illumination system L comprising two or more lamps and reflectors is flash energized to direct light rays upon the original to produce image rays corresponding to the informational areas on the original. The image rays are projected by means of an optical system 11 to an exposure station A for exposing the photosensitive surface of a moving xerographic plate in the form of a flexible photoconductive belt 12. In moving in the direction indicated'by the arrow, prior to reaching the exposure station A, that portion of the belt being exposed would have been uniformly charged by. a corona device 13 indicated at a belt run extending bement of the electrostatic image.

image projected from the original document. A discharge device, preferably a flourescent lamp'17 is provided adjacent support roller 16 for reasons to be explained hereinafter.

i As the belt surface continues its movement, the electrostatic image passes around the roller 16 to a developer station B located at a third run of the belt in which there is positioned developing apparatus generally indicated by the reference numeral 18. The developer apparatus 18 comprises a plurality of brushes adapted for rotation by a suitable motor 19 to carry developer along the adjacent surface of the upwardly moving inclined .photoconductive belt 12 to provide develop- The developed electrostatic image is transported be the belt 12 to a transfer station C located at a point of tangency on the belt around the drive roller whereat a sheet of copy paper is moved at a speed in synchronism with the moving belt in order to accomplish transfer of a properly registered developed imagejA transfer roller 20 is provided at transfer stationC for contacting the upper surface of the copy paper to assure good contact between the copy paper and the belt 12 during transfer of the toner imagefrom the belt tothe paper. An electrical bias may be provided on roller 20 to attract the toner from belt 12 to the-copy paper.

There is alsoprovided a copy sheet supplying apparatus comprising a main paper feed supply 21 and an auxiliary paperifeed supply 22. Each of the'paper supplies is adapted to separatesheets from their respective supply stacks and to transport the sheets to a sheet registration station and eventually into contact with the developedimage on thebelt as the same is carried around the drive roller 1 5. -Control means 23 are operatively associated with each of the paper supply mechanisms 21, 22 and the flash illumination device L for producing an electrostatic latent image on the; belt 12 to present a developed image at the transfer station C in timed sequence with the arrival of a sheet of paper, and is coordinated with the activation of other processing and control devices at the precise time that these elements are to function for their intended purpose. A paper sensing'device 24 is positioned adjacent the paper. path between the paper supply mechanism 21 and 22 and the trnsfer station C, to determine if the paper .is fed therefrom at the proper time relative to the image on the photoreceptor belt.

After the developed image is transferred to a sheet of paper, it is stripped from the belt 12 and conveyed by Y conveying system 25 into a fuser apparatus generally indicated by reference numeral 26 whereinthe developed and transferred xerographic powder image on the sheet material is affixed thereto; After fusing, the finished copy isdischarged from the apparatus by a conve yor 27 at a suitable point for collection externally of the apparatus. The toner particles remaining asresidue on the developed image and those particles nototherv.As stated heretofore, in a high speed copierofithe" type illustrated, a number of imagesmay have flashed on the belt by the time thesheet of paper is fed for transfer of the foremost image thereto. In the event of a malfunction in the paper feed mechanism which would be sensed by the sensor 24, a number of operations are immediately instituted to avoid deleterious effects on the machine caused by developed images reaching the transfer station in the absence of copy paper thereat. Therefore, upon the sensing of a paper.

misfeed by sensor 24 the control system 23 is adapted to immediately energizevlamp 17, deactivate the developer motor 19, remove the electrical bias on transfer roller 20 and move the transfer roller out of contact with the belt by a suitable mechanism (not shown).

Thus in the event of a paper misfeed, the electrostatic image on the belt passing beneath lamp 17 will be discharged, those images that are passed the lamp when the misfeed is detected and have not reached the developer will not be developed and those images that are developed when the misfeed is detected will not, be

transferred to the transfer roll since the electrical bias thereon is removed and the roll is withdrawn from the belt. Therefore the cleaning station will onl'y'be required to remove toner from one or two developed images rather than all the images that were on the belt prior to the detection of the misfeed.

While we have described the preferred embodiment of our invention it is to be understood that the invention is not limited thereto but maybe otherwise embodied within the scope of the following claims.

What is claimed isi 1. In a reproduction machine adapted for making copies of an original through a plurality of process steps continuously energizing the transfer roller and main- 'taining the transfer roller in contact with the photoconductive surface during a normal copy run; removing the electrical bias on the transfer roller moving the transfer roller away from the photoconductive surface in the event of a paper misfeed to prevent transfer of toner to the roller; and, de-energizing the developer to prevent development of latent electrostatic images passing by the developer subsequent to a paper misfeed. 2. A method to minimize toner consumption and toner contamination-of a reproduction machine according to claim 1 further including a step of discharg-' ing the latent electrostatic images on the photodonduc tive surface before the imaged areas reach the developer to prevent development thereof in the event of a paper misfeed.

3. In a reproduction machine adapted for making copies of an original through a plurality of process steps including exposure of the original to form a latent electrostatic image of the original on a photoconductive surface, developing the image to provide a toner image of the original on the photoconductive surface, and holding the copy paper against the toner image by suitable holding means adapted for continuous contact 6 v with the photoconductive surface during normal mation of the machine comprising the steps of; chine operation to transfer the toner image to the copy discharging a portion of the latent imaged areas on paper, a method to minimize toner consumption and the photoconductive surface in the event of a paper toner contamination of the machine comprising the misfeed and preventing development of undissteps of: 5 charged imaged areas on the photoconductive surmoving the holding means away from the photoconface by de-energizing the developer. ductive surface in the event of a paper misfeed to pre- 6. A method for automatically producing copies of an vent transfer of toner thereto and discharging latent original comprising the steps of; image areas on the photoconductive surface in the providing an electrostatic charge pattern of the origievent of a paper misfeed to prevent development 0 nal on a photoconductive surface; thereof. developing the charge pattern wit an electrically at- 4. A method to minimize toner consumption and tractable powder as the charge pattern on the photoner contamination of the machine according to claim toconductive surface passes a developer station to 3 further including the step of preventing development provide a powder image on the photoconductive of the imaged areas that are not discharged by desurface in conformity with the original; energizing the developer. supplying sheets of copy paper to the photoconduc- 5. In a reproduction machine adapted for making tive surface in synchronism with the developed copies of an original through a plurality of process steps image thereon for contact with the image to transincluding exposure of the original to form a latent elecfer the powder image to the copy paper; and, trostatic image of the original on a photoconductive discharging the electrostatic charge pattern in the surface, developing the image to provide a toner image event of a paper misfeed to prevent development of the original on the photoconductive surface, and of the charge pattern as the photoconductive surtransferring the toner image to a copy paper, a method face moves past the developer station. to minimize toner consumption and toner contamina- 

1. In a reproduction machine adapted for making copies of an original through a plurality of process steps including exposure of the original to form a latent electrostatic image of the original on a photoconductive surface, developing the image to provide a toner image of the original on the photoconductive surface, providing an electrical bias on the copy paper and holding the copy paper against the toner image by means of an electrically biased transfer roller to transfer the toner image to the copy paper, a method to minimize toner consumption and toner contamination of the machine comprising the steps of: continuously energizing the transfer roller and maintaining the transfer roller in contact with the photoconductive surface during a normal copy run; removing the electrical bias on the transfer roller moving the transfer roller away from the photoconductive surface in the event of a paper misfeed to prevent transfer of toner to the roller; and, de-energizing the developer to prevent development of latent electrostatic images passing by the developer subsequent to a paper misfeed.
 2. A method to minimize toner consumption and toner contamination of a reproduction machine according to claim 1 further including a step of discharging the latent electrostatic images on the photoconductive surface before the imaged areas reach the developer to prevent development thereof in the event of a paper misfeed.
 3. In a reproduction machine adapted for making copies of an original through a plurality of process steps including exposure of the original to form a latent electrostatic image of the original on a photoconductive surface, developing the image to provide a toner image of the original on the photoconductive surface, and holding the copy paper against the toner image by suitable holding means adapted for continuous contact with the photoconductive surface during normal machine operation to transfer the toner image to the copy paper, a method to minimize toner consumption and toner contamination of the machine comprising the steps of: moving the holding means away from the photoconductive surface in the event of a paper misfeed to prevent transfer of toner thereto and discharging latent image areas on the photoconductive surface in the event of a paper misfeed to prevent development thereof.
 4. A method to minimize toner consumption and toner contamination of the machine according to claim 3 further including the step of preventing development of the imaged areas that are not discharged by de-energizing the developer.
 5. In a reproduction machine adapted for making copies of an original through a plurality of process steps including exposure of the original to form a latent electrostatic image of the original on a photoconductive surface, developing the image to provide a toner image of the original on the photoconductive surface, and transferring the toner image to a copy paper, a method to minimize toner consumption and toner contamination of the machine comprising the steps of; discharging a portion of the latent imaged areas on the photoconductive surface in the event of a paper misfeed and preventing development of undischarged imaged areas on the photoconductive surface by de-energizing the developer.
 6. A method for automatically producing copies of an original comprising the steps of; providing an electrostatic charge pattern of the original on a photoconductive surface; developing the charge pattern wit an electrically attractable powder as the charge pattern on the photoconductive surface passes a developer station to provide a powder image on the photoconductiVe surface in conformity with the original; supplying sheets of copy paper to the photoconductive surface in synchronism with the developed image thereon for contact with the image to transfer the powder image to the copy paper; and, discharging the electrostatic charge pattern in the event of a paper misfeed to prevent development of the charge pattern as the photoconductive surface moves past the developer station. 